Filament crimping

ABSTRACT

Two separate filament structures are crimped simultaneously but at different temperatures to produce a combined filament structure having two levels of crimp.

United States Patent 11 1 Hume et al. 28/72.l7

Erickson Nov. 12, 1974 [5 FILAMENT CRlMPlNG 3.115.744 12/1963 N611 57 157 8 3.175.348 3/1965 [75] wayne Erckson Greemmc 3.199.281 8/1965 MilelOV 61111. 57 140 8 73 Assignee; i i petroleum Company, 3,234,624 2/ 1966 Shuttuck 28/111 Bartlesvme Okla 3,384,932 5/1968 Watson 19/65 T 3.387.349 6 1968 1111116111: Cl 111. 28/72.]4 x [22] Filed: Jan. 5, 1972 3,408,251 10 1968 01111111 Cl 111. 28/7217 x 3.423.809 1/1969 8611111111 28/7217 PP 215,461 3,601,872 8/1971 P0111111 et 111.... 28/].3 3,653,198 4/1972 Hopkins 28/7217 [52] CL D 28/7214 3.681.821 8 1972 Buck 2.8/1.3 [51] Int. Cl D02g l/l2 [58] Field 61 Search 28/1.6, 1.2, 1.3, 72.1, Emmmepmus 264/168, 282-, 57/140 B, 157 s [57] ABSTRACT Two separate filament structures are crimped simulta- [56] References Cited neously but at different temperatures to produce 8 UNITED STATES PATENTS combined filament structure having two levels of 2,810,281 10/1957 Appleton et 111. 28/72.17 x 3,039,171 6/1962 4 Claims, 1 Drawing Figure PAIENIEDIIBV 121914 3Q846l881 INVENTOR. W. K. ERICKSON A T TOR/V5 rs I 1 FILAMENT CRIMPING BACKGROUND OF INVENTION This invention relates to a method and apparatus for crimping filament structures and to the crimped prod- LlCt.

Often it is desirable to crimp synthetic filament structures to increase the bulk and cover, improve the hand, etc. In many instances it is preferred to avoid having the crimp in register, that is having the crimp loops of SUMMARY OF INVENTION I have found that crimped filament structures can be made by simultaneously stuffer crimping in one crimper at least two portions of the structure which are at different temperatures when fed to the crimper. Fur-- ther according to my invention a single filament structure is divided into at least two portions and one portion is heated before feeding to the crimper. Further according to my invention a filament structure produced by simultaneous crimping of at least two portions of the structures at different temperatures in a single crimper, is chopped to produce crimped staplefibers.

My invention also includes apparatus for performing the process described above and the resulting products.

DETAILED DESCRIPTION In the drawing a stuffer crimper 11 comprises crimper rolls 12 and 13, inlet guide 14 and body 16. A heater 17 is provided in the path of the portion of the feed to the crimper, and guide rolls 18 and 19 are provided in a separate path to the crimper. Guide rolls 20 and 21 are provided for the combined filament struc ture.

In operation a tow 22 passes over guide roll 20, is divided into two filament structure portions 23 and 24. Portion 23 passes over heater l7 and then to guide roll 21 while portion 24 passes around guide rolls l8 and 19' through a path in which it is not subjected toheating by heater l7. Portions 23 and 24 are recombined on guide roll 21 and fed into stuffer crimper 11. The crimped product from crimper 11 is removed therefrom for further handling as desired and necessary. This can include for example takeup rolls for packaging or the yarn can be sent directly to further processing, for example, choppingto produce staple fibers.

EXAMPLE In an example according to my invention, utilizingthe apparatus described above, a 5,000 denier, 280 filament, drawn polypropylene tow was supplied to stuffer crimper 11 having one-fourth inch face width crimper rolls, at 40 meters per minute. One-half of the tow (2,500 denier) was routed over heater 17 which was a draw shoe type surface heater with temperature control and controlled at 400F. surface temperature. The other half of the tow (2,500 denier) was passed over guide rolls 18 and 19 out of contact with heater 17. The two halves were recombined at roll 21 and were crimped in crimper 11. The resulting crimped tow had two distinct crimp levels.

For comparison, holding the stuffer box pressure and the crimper roll pressure constant, the portion of the tow passing over heater 17 was guided away from the surface thereof whereby the two portions of the tow were fed to crimper 11 at substantially the same temperature. The resulting tow had near uniform, one level crimp.

This example illustrates the effectiveness of the apparatus and method according to my invention to produce a crimped tow having two levels of crimp and demonstrates further that this result is not obtained merely by dividing the tow into two parts without heating one of the parts.

Throughout the application and in the claims the term filament structure has been used to include all crimpable filaments including yarns, tows, slivers, rovings, etc. The material from which the filaments are made can be any material which produces crimpable filaments including, for example, polypropylene, nylon, polyester, etc.

Reasonable variation and modification are possible within the scope of my invention. For example, means other than surface heaters can be used for heating one portion of the filament structure including such means as radiant heaters, contact with heated fluid, etc. Means other than the guide rolls can be used for providing the separate paths for the filament portions. The temperatures of thetwo portions which are combined and fed to the crimper can vary widely depending upon the condition of the structure to be processed and the results desired. The cooler of the two portions can be at ambient temperature or can be below or above ambient temperature. The temperature of the warmer portion should be sufficiently above that of the cooler portion to give the desired variation in crimp level and the resulting product. In general, the larger the temperature differential the more noticeable will be the resulting two crimp level in the product. Although the invention has been described and presently finds its greatest application in systems in which the feed to the crimper is divided into only two parts, the invention also is applicable to systems in which the feed is divided into three or more portions at different temperature levels.

The term crimp level in this application is used to mean crimp frequencies and amplitudes as well as the nature of the crimping, i.e., the shape of the crimp loops, and a variation in crimp level can be in any one or more of these elements of crimp. For example, two crimp levels are obtained when two crimp frequencies are obtained even though the amplitude may be substantially the same. However, more commonly, when practicing my invention differences in both frequency and amplitude result.

What is claimed is:

l. A method of producing a crimped filament structure comprising passing a first portion of said filament structure into a stuffer crimper at a first temperature;

recombining said first and second portions; and

passing said recombined portions to a stuffer crimper whereby said first and second portions are simultaneously subjected to crimping conditions at substantially different temperatures producing a filament structure having crimp variations between individual filaments thereof.

3. The method of claim 2 wherein said filament structure having crimp variations is cut to produce staple fibers.

4. The method of claim 2 wherein said second portion of filament structure is heated by passing said second portion in proximity to heating means. 

1. A method of producing a crimped filament structure comprising passing a first portion of said filament structure into a stuffer crimper at a first temperature; simultaneously passing a second portion of said filament structure into said stuffer crimper at a second temperature substantially higher than said first temperature; and simultaneously subjecting said first portion and said second portion to crimping conditions in said stuffer crimper thereby producing a filament structure having crimp variations between individual filaments thereof.
 2. A method of producing a filament structure comprising dividing a filament structure into a first portion and a second portion; heating said second portion to a temperature substantially above the temperature of said first portion; recombining said first and second portions; aNd passing said recombined portions to a stuffer crimper whereby said first and second portions are simultaneously subjected to crimping conditions at substantially different temperatures producing a filament structure having crimp variations between individual filaments thereof.
 3. The method of claim 2 wherein said filament structure having crimp variations is cut to produce staple fibers.
 4. The method of claim 2 wherein said second portion of filament structure is heated by passing said second portion in proximity to heating means. 